3. DEFINITION
Rheumatic fever (RF)
It is a systemic, post-streptococcal,
nonsuppurative inflammatory disease,
principally affecting the heart, joints, central
nervous system, skin and subcutaneous
tissues.
The chronic stage of RF involves all the layers
of the heart (pancarditis) causing major cardiac
4. INCIDENCE
Age:-
The disease appears most commonly in children
between the age of 5 to 15 years when the
streptococcal infection is most frequent and intense.
Sex:-
Both the sexes are affected equally, though some
investigators have noted a slight female
preponderance.
The geographic distribution,
incidence and severity of RF and RHD are generally
5. The disease is seen more commonly in
Poor socioeconomic strata of the society
Living in damp and overcrowded places which
promote interpersonal spread of the streptococcal
infection.
Its incidence has declined in the developed
countries as a result of
improved living conditions
early use of antibiotics in streptococcal
infection.
6. MORPHOLOGIC FEATURES
RF is generally regarded as an autoimmune focal
inflammatory disorder of the connective tissues
throughout the body.
Cardiac lesions of RF in the form of pancarditis,
particularly the valvular lesions, are its major
manifestations.
Extracardiac lesions –
However, supportive connective tissues at other sites
like the synovial membrane, periarticular tissue, skin
and subcutaneous tissue, arterial wall, lungs, pleura
7. A. Cardiac Lesions
The cardiac manifestations of RF are in the form of
focal inflammatory involvement of the interstitial
tissue of all the three layers of the heart, the so-
called pancarditis.
The pathognomonic feature of pancarditis in RF is
the presence of distinctive Aschoff nodules or
Aschoff bodies.
8. THE ASCHOFF NODULES (BODIES)
The Aschoff nodules or the Aschoff bodies are
spheroidal or fusiform distinct tiny structures, 1-2 mm
in size,
occurring in the interstitium of the heart in RF and
may be visible to naked eye.
They are especially found in the vicinity of small blood
vessels in the myocardium and endocardium
occasionally in the pericardium and the adventitia of
the proximal part of the aorta.
Lesions similar to the Aschoff nodules may be
9. Evolution of fully-developed Aschoff bodies occurs
through 3 stages all of which may be found in the
same heart at different stages of development.
These are as follows:
1. Early (exudative or degenerative) stage
2. Intermediate (proliferative or granulomatous)
stage
3. Late (healing or fibrous) stage
10. 1. Early (exudative or degenerative) stage
The earliest sign of injury in the heart in RF is
apparent by about 4th week of illness.
Initially,
there is oedema of the connective tissue and
increase in acid mucopolysaccharide in the ground
substance.
This results in separation of the collagen fibres by
accumulating ground substance.
Eventually,
the collagen fibres are fragmented and disintegrated
and
the affected focus takes the appearance and
11. 2. Intermediate (proliferative or granulomatous)
stage
It is this stage of the Aschoff body which is
pathognomonic of rheumatic conditions (Fig. 14.25).
This stage is apparent in 4th to 13th week of illness.
The early stage of fibrinoid change is followed by
proliferation of cells that includes infiltration by
lymphocytes (mostly T cells), plasma cells, a few
neutrophils and
the characteristic cardiac histiocytes (Anitschkow
12. Cardiac histiocytes or Anitschkow cells are
present in small numbers in normal heart
But their number is increased in the Aschoff
bodies;
therefore they are not characteristic of RHD.
Anitschkow cells are large mononuclear cells
having central round nuclei and contain
moderate amount of amphophilic cytoplasm.
13. •The nuclei are vesicular and contain prominent central chromatin
mass
which in longitudinal section appears serrated or caterpillar-like,
while in cross-section the chromatin mass appears as a small
rounded body in the centre of the vesicular nucleus, just like an
owl’s eye.
14. Some of these modified cardiac histiocytes become
multinucleate cells containing 1 to 4 nuclei and are
called Aschoff cells and are pathognomonic of RHD.
15.
16.
17. 3. Late (healing or fibrous) stage
The stage of healing by fibrosis of the Aschoff
nodule occurs in about 12 to 16 weeks after the
illness.
The nodule becomes oval or fusiform in shape,
about 200 μm wide and 600 μm long.
The Anitschkow cells in the nodule become
spindle-shaped with diminished cytoplasm and
the nuclei stain solidly rather than showing
vesicular character.
These cells tend to be arranged in a palisaded
manner.
With passage of months and years,
the Aschoff body becomes less cellular and
the collagenous tissue is increased.
Eventually,
18.
19. RHEUMATIC PANCARDITIS
Although all the three layers of the heart are affected in
RF,
the intensity of their involvement is variable.
1. RHEUMATIC ENDOCARDITIS
Endocardial lesions of RF may involve the valvular and
mural endocardium, causing
rheumatic valvulitis and
mural endocarditis, respectively.
Rheumatic valvulitis is chiefly responsible for the major
cardiac manifestations in chronic RHD.
20. RHEUMATIC VALVULITIS
Grossly,
The valves in acute RF show thickening and loss of
translucency of the valve leaflets or cusps.
This is followed by the formation of characteristic,
small (1 to 3 mm in diameter), multiple, warty
vegetations or verrucae, chiefly along the line of
closure of the leaflets and cusps.
These tiny vegetations are almost continuous so
that the free margin of the cusps or leaflets appears
as a rough and irregular ridge.
21. The vegetations in RF appear grey-brown, translucent
and are firmly attached
so that they are not likely to get detached to form
emboli,
unlike the friable vegetations of infective
endocarditis.
Though all the four heart valves are affected, their
frequency and severity of involvement varies:
mitral valve alone being the most common site,
followed in decreasing order of frequency, by
combined mitral and aortic valve (Fig. 14.26).
The tricuspid and pulmonary valves usually show
infrequent and slight involvement.
22. The higher incidence of vegetations on left side of the
heart is possibly because of the greater mechanical
stresses on the valves of the left heart, especially
along the line of closure of the valve cusps (Fig.
14.27, A).
The occurrence of vegetations
on the atrial surfaces of the atrioventricular valves
(mitral and
tricuspid)
on the ventricular surface of the semilunar valves
(aortic and
